Bicyclus anynana
Squinting bush brown | |
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B. a. anynana, Harenna Forest, Ethiopia | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Class: | Insecta |
Order: | Lepidoptera |
Family: | Nymphalidae |
Genus: | Bicyclus |
Species: | B. anynana
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Binomial name | |
Bicyclus anynana | |
Synonyms | |
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Bicyclus anynana (squinting bush brown) is a small brown
The bush brown is helpful for research because of its ideal size and breeding time. In addition to this, the bush brown is one of many insect species to vary its coloration depending on the season,[5] making it a valuable tool in studying phenotypic plasticity. Wet seasons produce butterflies with large eyespots, while dry seasons have butterflies dull in color.[6]
Male butterflies engage in
Description
The bush brown is a small brown butterfly with a
Role in research
Originally the bush brown was collected to study evolutionary and ecological genetics. This research is now primarily used to see how the environment shapes the phenotypic evolution of the butterfly.[5]
The squinting bush brown is an ideal butterfly for conducting research. Its relative small size makes it easy to breed and care for, while it is large enough to place tags on and surgically manipulate. Their phenotypic plasticity in life history traits, wing patterns, and seasonal habits combined with the fact that their entire genome has been sequenced makes them ideal subjects in understanding how the environment effects genes.[3]
Yi Peng Toh, Emilie Dion and Antonia Monteiro use this species in their paper 'Dissections of Larval, Pupal and Adult Butterfly Brains for Immunostaining and Molecular Analysis', with a full rationale. PMID: 34449688
Taxonomy
The squinting bush brown is of the genus Bicyclus and the family Nymphalidae. It belongs to the order Lepidoptera. It is separated into three distinct subspecies; B. anynana anynana, B. a. centralis, and B. a. socotrana.[12]
The squinting bush brown is found in eastern Africa. B. a. anynana can be found from Kenya to Tanzania and Ethiopia as well as in Zambia, Malawi, Mozambique, Rhodesia, Botswana, South Africa, and the Comoro Islands.[13] B. a. centralis is present in Uganda, southern Zaire, eastern Zaire, and northern Angola.[13] Bicyclus anynana socotrana is predominantly located in Socotra Island.[13]
As the squinting bush brown is widespread and common throughout its distribution, its conservation status is secure and has no reported management needs.[12]
Life cycle
The squinting bush brown can live up to half a year in the wild and reaches sexual maturity around 2 weeks.[14]
The
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Egg
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Egg on a corn (Zea mays) leaf with caterpillar visible through the egg shell
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Larva
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Head of the caterpillar
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Chrysalis
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Adult from a lab strain
Habitat and feeding
Squinting bush browns are normally woodland butterflies. They can be found flying close to the ground. They are primarily found in eastern parts of Africa, mainly in the countries of Uganda, Ethiopia, Kenya, Tanzania, Mozambique, and Zimbabwe.[16] The larval diet consists of several species of grass and the adult butterflies feed on fruit that is on the ground.[5] Species of butterflies that feed on fruit have been found to have the longest life spans. The butterflies feed on fruit as opposed to nectar simply as a matter of availability, but it has been discovered that butterflies feeding off of fruit had better offspring.[4][17] When the butterflies are in the caterpillar stage, they can use several species of Poacae as larval host plants.[16]
Mud puddling
The squinting bush brown has been known to participate in the phenomena of
Mating
There are six steps that males take in order to mate with a female: location, orientation, flickering, thrust, attempting, and copulation.
It has also been discovered that adults during the wet season reproduce quickly while the dry season adults use resources geared towards prolonged survival. During the dry season, females are more likely to produce fewer but larger eggs. They have a higher parental investment in each offspring.[8] This characteristic has made them vital in research on phenotypic plasticity.[5]
Male courtship rate plasticity
Courtship rate plasticity is a change in the rate of stereotypical courtship behavior changes when faced with different environmental factors, such as temperature.[9] Male courtship rates of the squinting bush brown butterfly exhibit a degree of plasticity. Studies have shown that these butterflies will change their courtship rate depending on temperatures throughout their larval stage into their adult stage.[9]
Researchers investigated the critical period for courtship rate plasticity to determine whether or not it differed from the critical period for wing pattern plasticity, which had already been established as the final larval instar.[9] In the squinting bush brown butterfly, high temperatures of around 27 degrees Celsius led to increased courtship by males, but low temperatures of 17 degrees Celsius led to males courting females at a much lower rate.[19] This courtship rate plasticity of the butterflies demonstrates their active adaptation to the current environment.[19]
This change in courtship rate, however, only occurs when the squinting bush brown butterfly is exposed to different temperatures at particular life stages: the temperature individuals experiences during their
Researchers at Yale University have discovered that the temperature at which the larvae are raised has an effect on the imago's sexual behaviour.[10] Females raised in a cooler environment are more likely to actively court male butterflies. In a warmer environment, the male butterflies traditionally take on the active role in courtship.[10]
Elder male preference
In the squinting bush brown butterfly, there has been a peculiar trend in terms of the mating males: older males seem to have a distinct mating advantage.
Inbreeding
Squinting bush browns are one of the first instances of insects severely affected by
Eyespots
Mating
Females have also been known to choose a mate depending on their
Defense and predation
As is common with a wide variety of lepidopterans, eyespots located on the wings are a common defensive mechanism for the squinting bush brown.[11] There are two predominant theories on why these eyespots have evolved. The first one is the large eyespots look similar to the eyes of predator's adversary. This temporarily surprises the predator allowing the butterfly to escape. A second potential benefit is that peripheral eye spots bring attention to non-essential body parts.[11] The bird will be more likely to attack the wings, as opposed to the body. More often than not, if the first predator strike fails the butterfly will be likely to escape.[11] These eyespots are most effective against the most common of the bush brown's predators, birds.[10]
Phenotypic plasticity
In particular it has a
References
- ^ "Afrotropical Butterflies: File E – Nymphalidae – Subtribe Mycalesina". Archived from the original on 2014-02-22. Retrieved 2012-05-14.
- PMID 12927132.
- ^ a b Bicyclus at Markku Savela's Lepidoptera and Some Other Life Forms
- ^ PMID 19081752.
- ^ a b c d e f g h i j Brakefield, Paul M., Patrícia Beldade, and Bas J. Zwaan. "The African butterfly Bicyclus anynana: a model for evolutionary genetics and evolutionary developmental biology." Cold Spring Harbor Protocols 2009.5 (2009): pdb-emo122.
- ^ S2CID 3341270.
- ^ .
- ^ S2CID 40508270.
- ^ PMID 23717531.
- ^ a b c d e Female butterflies chase males when it's cool
- ^ ISBN 978-1-86872-724-7.
- ^ a b Larsen, T.B. 2011. Bicyclus anynana. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.1. <www.iucnredlist.org>
- ^ a b c Jong, M.A. de, 2010, Doctoral Thesis, Leiden University
- ^ Pijpe et al. (2008), Increased life span in a polyphenic butterfly artificially selected for starvation resistance
- S2CID 221678693.
- ^ a b Larsen, T.B. 2011. Bicyclus anynana. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.1
- S2CID 18940240.
- ^ a b c d e Saccheri, Ilik, Paul Brakefield, and Richard Nichols. "Severe Inbreeding Depression and Rapid Fitness Rebound in the Butterfly Bicyclus Anynana." Society for the Study of Evolution 50.5 (1996): 2000–013
- ^ PMID 15058439.
- ^ a b Robertson DN, Sullivan TJ, Westerman EL. Lack of sibling avoidance during mate selection in the butterfly Bicyclus anynana. Behav Processes. 2020 Apr;173:104062. doi: 10.1016/j.beproc.2020.104062. Epub 2020 Jan 22. PMID: 31981681